One giant step for mankind and conservation. When Nash wrote 'Song of the Open Road' the outdoor advertising industry was largely unregulated and gobbling up the roadside views of American byways. It wasn't until Ladybird Johnson took aim at the industry in the 60's and banned most advertising billboards from U.S. interstates. States and municipalities followed suit with tighter restrictions.
Invariably one of the most referenced Nash poems today, Song of the Open Road leapfrogged off of Joyce Kilmer's 'Trees'. The poem often appears in articles about conservation of forests and trees like this one in India.